Investigation of the electro-oxidation of artificial Black Sea water using cyclic voltammetry on metal sulfide electrodes (I)

• Black Sea water containing H2S was offered as a fuel cell fuel.
• Metal sulfides were examined as the anode material for H2S Fuel Cells.
• It was found that NiS is the most suitable catalyst towards the oxidation of HS− ions.

Black Seawater is an alternative hydrogen source because it has hydrogen sulfide content. Seawater electrolysis is a promising method to produce hydrogen. The anodic oxidation of hydrogen sulfide is a novel approach for directly generating electricity via fuel cells. Therefore, four materials (Cu, Stainless Steel 304 (SS), V2O5 and Ni) were examined in artificial seawater containing hydrogen sulfide (HS−). We developed active metal sulfide electrodes for oxidizing HS−. Alongside the corrosion potentials, the progression of the oxidation and reduction reactions was obtained by the cyclic voltammetry method. The active behaviors of the metal sulfide (MSx) layers were determined by applying Electrochemical Impedance Spectroscopy (EIS). Although the Cu2S electrode acts as the active catalyst during HS− ion oxidation, NiS is the most suitable metal sulfide because it exhibits a higher corrosion resistance than Cu2S. While V2O5 demonstrates catalytic activity at high temperatures (≥30 °C), FeS layers corrode easily in the artificial seawater environment.